Spike Milligan's fourth volume of war memoirs, Mussolini: His Part in My Downfall, spans the landing in Salerno, Italy, September 23, 1943, to his being invalided. While this is only four months, the text is nearly as long as the three earlier volumes together. Although the humorous writing is similar, there are no ersatz communiques and almost no sketches; the photographs are fewer and smaller.
Losing patience with criticism about his veracity, the preface reads, "I’ve spent a fortune on beer and dinners interviewing my old Battery mates, and phone calls to those overseas ran into over a hundred pounds." Also, "I wish the reader to know that he is not reading a tissue of lies and fancies, it all really happened." (Following this book Milligan was even more upset, by comments from the people he wrote about. His manager Norma Farnes wrote that she thought the next volume would never be written on their account.) Farnes wrote that Milligan's diary was kept daily, except when the fighting was too fierce but there are also days when he is too sick or bored to write. Sometimes the diaries of others supplement Milligan's in the text.